The present invention is related to chest-patch bio-electic interface adapters and more specifically, in its preferred embodiment, to a bio-electic interface adapter comprising safe and effective large area defibrillation electrodes in functional combination with sufficient additional precordial electrodes to allow multiple lead ECG monitoring, including international standard twelve lead monitoring, said defibrillation electrodes being optionally employed as Right Arm and Left Leg electrodes.
Conventional medical analysis and therapy often involves use of a plurality of individual electrodes, each applied independently to an appropriate location on a subject""s body by way of electrically conductive paste, and securing means such as a skin compatible adhesive. A relevant example of use is in the monitoring of Electrocardiogram (ECG) signals at precordial; and at left and right arm, and left Leg locations by independent electrodes in an Einthoven triangle configuration.
Further, it is known to apply individual non-invasive precordial electrodes to a subject""s chest to allow not only the acquiring of ECG data, but to allow administration of therapy, such as defibrillation of fibrillating hearts the pacing of arrested hearts and the like.
A problem which presents in the use of such independent electrodes, however, (particularly outside-of-hospitals), is that reliable, repeatable placement upon a subject""s body is difficult. For instance, it is generally accepted that a majority of the errors encountered in acquiring ECG data, (particularly that to be archived for serial comparison), is caused by improper electrode placement by medical technical staff.
Of relatively recent development are flexible electrode pads which comprise a multiplicity of electrodes affixed thereto in an appropriate pattern for use in medical analysis and/or therapy. For instance, a Patent to Manoli, No. 4,583,549 describes an ECG electrode chest pad in which six (6) conductive discs are plated and etched on a flexible adhesive pad in a clinically conventional predetermined pattern effective for precordial 12 lead ECG electrode placement. Reproducible attachment of said six electrodes to a subject""s chest in the proper arrangement for use with standard ECG machines is thus made possible by a single application of an electrode pad of an appropriate size for use with any particular subject. However, it would seem that the Manoli system would require a host of numerous sized electrode pads to accommodate subjects of different sizes as the Claims recite rather strict electrode placement criteria which are referenced with respect to a subject""s body. A single electrode pad would not meet said requirements on subjects of different sizes. In addition, conductive discs made by plating and etching may not provide optimal electrodes for twelve lead ECG monitoring. A U.S. Pat. No. 4,121,575 to Mills et al. describes a multiple electrode device for application to a subject""s chest, formed in stretchable non-conductive material having apertures in the V1-V6 positions. The capability for stretching the material is held to allow accurate positioning of V1-V6 electrodes on subjects of differing body size. It is noted that material under tension can lead to less than optimum subject fit and electrode operational characteristics in clinical settings. A Patent to Groeger et al., U.S. Pat. No. 4,957,109 describes an electrode assembly comprising right and left arm and leg leads, and precordial leads all affixed to a common structure. The arm and leg leads do not affix to a subject""s chest during use. The Mills et al. and Groeger et al. systems do not serve to maintain a relatively fixed positioning of electrodes therein during use, and it is noted that movement between electrodes during use frequently causes confounding noise generation in electrocardiography systems. This is particulalry true where motion occurs between Limb Lead forming electrodes. Another U.S. Pat. No. 5,327,888 to Imran describes a precordial electrode strip which is supplied with detachable RA, LA and LL limb leads, which detachable limb leads are applied to subject limbs in use.
Patents to Way et al., U.S. Pat. Nos. 4,955,381 and 5,080,099 describe multiple conductive polymer pad containing electrodes for performing multiple electrical physiological functions from a set of electrodes with respect to a subject, at or about the same time, such as defibrillation, pacing and monitoring. Other Patents which disclose multiple electrode assemblies are U.S. Pat. No. 4,328,814 to Arkans and U.S. Pat. No. 5,191,886 to Paeth et al. These Patents each describe a plurality of electrodes configured in a physically seriesed configuration with conductive leads to various physically seriesed contacts, present at one end thereof. In addition, a Patent to Collins, U.S. Pat. No. 3,612,061 describes a porous sheet of elastic material which supports an array of electrodes adapted to contact a wearer""s skin, and U.S. Pat. No. 5,184,620 to Cudahy et al. describes an electrode pad system comprised of a multiplicity of electrodes which are utilized in defibrillation and pacing scenarios as directed by an on-line computer driven analysis and electrical energy application system, which system distributes electrical energy to appropriate sets of said multiplicity electrodes in response to subject needs.
Continuing, it is to be understood that particularly appropriate materials in which to form an electrode pad with a plurality of ECG monitoring electrodes present therein are hydropolymers. This is because hydropolymers can be pliable, self-adhesive and compatible with maintaining the requisite hydration, (and consdquent mechanical and electrical stability), of subject skin to which they affix during prolonged use. The pliable property makes hydropolymers exceptionally well suited for application to unpredictable surface irregularities of various subject""s chests and the self-adhesive property negates the need to apply non-aquous based or other potentially subject skin irritating adhesive material to affix the present invention to a subject""s body during use. As well, the need to separately apply electrically conductive paste to electrically conducting areas of electrodes becomes unnecessary.
A U.S. Pat. No. 5,331,959 to Imran, describes a low impedance dry conforming contact member in which are present rods or filaments which are cured into material such as a silicon-based material, such that when configured as an electrode provide impedance reducing projections which protrude into the pores of a subject""s skin during use. Said rods or filaments are held to reduce the need to use conductive paste. Another U.S. Pat. No. 4,524,087 to Engel, describes a conductive electrode application comprising an adhesive, swellable, dermally-nonirritating, conformable, ionic hydropolymer biomedical electrode fabricated by a claimed process.
Continuing, three Patents to Keusch et al, U.S. Pat. Nos. 4,706,680, 4,989,607 and 5,143,071 describe hydrogels which are caused to be highly conductive by the inclusion of an essentially uniformly distributed active electrolyte therein. Said Patents state that to form the hydrogels a polymeric mixture is caused to become cross-linked by exposure to radiant energy. This causes a gel-like solid to form which is sufficiently tacky and adhesive to adhere to subject""s skin and which is substantially non-stringy and non-aggressive so that subject comfort is protected.
A Patent to Highe et al., U.S. Pat. No. 5,289,822 describes an electrode formed of a dry-conductive material having an outer surface for placement in contact with a subject""s skin. A composition is deposited on at least a portion of the surface of the dry-electrode which comprises a plurality of water-containing vesicles. The purpose of said water-containing vesicles being to effect an immediate lowering of subject skin resistance upon the application of the electrode. It is stated that a period of approximately four minutes is otherwise required for moisture from a subject""s skin to naturally occur at the electrode.
A Patent to Schmid, U.S. Pat. No. 5,124,107 describes a process for manufacturing a body electrode which comprises one or more galvanically active sensors which are combined with a first layer capable of adhering to a subject""s skin, on a body contact side thereof. A second covering or supporting layer is also present on the opposite side of the body electrode. The process for manufacture provides that the two layers are sequentially cast in a mold which provides intended shape and size. The procedure avoids manufacturing problems encountered where electrodes are stamped from a preformed sheet. A potential problem of using such an electrode as provided by the Schmid 107 Patent is that it provides a laterally oriented conductive path between said galvanically active sensors through the first layer thereof. Electrically anisotropic conducting hydropolymers would be preferable.
Continuing, a Patent to Suyama et al, U.S. Pat. No. 5,132,058 describes a process for producing an anisotropically electroconductive sheet having a plurality of electroconductive portions extending in the direction of the thickness of the sheet. Application of an anisotropic magnetic field is utilized to draw electroconductive particles into a molding material such that said electroconductive particles gather where said electromagnetic field is applied. Another Patent which describes a similar system to that achieved by practice of the Suyama et al. Patent is U.S. Pat. No. 4,778,635 to Hechtman et al. A Patent to Kashiro et al., U.S. Pat. No. 4,209,481 describes an anisotropically electroconductive sheet in which electroconductive wires are formed into patterned groupings, which patterned groupings are in turn formed into patterns. The wires are parallel in the direction of the sheet thickness, and spaced apart by non-electroconductive elastomer. Another U.S. Pat. No. 5,045,249 to Jin et al., describes electrical interconnections made by means of a layer or sheet medium comprising chains of magnetically aligned, electrically conductive particles in a nonconducting medium. End particles of chains protrude from a surface of the medium to effect electrical contact. A Patent to Abraham et al. describes an electrode for use with electrosurgical apparatus which provides capacitive coupling with the skin of a subject. The electrode includes a conductive plate connected to the electrosurgical apparatus with an insulating layer disposed in contact with the conductive plate and on the opposite face of the insulator there is provided conductive material in the form of a plurality of discrete islands of conductive adhesive material which contact the skin of a subject during use. Another U.S. Pat. No. 5,232,639 to Reitz et al. describes a process for forming articles with anisotropic void distributions therein.
Of recent issue is a Patent to Kelly et al. U.S. Pat. No. 5,916,159, which describes an electro-dermal connector device with electrodes present therein for monitoring twelve lead ECG""s. This Patent Claims spacing between precordial electordes V1-V2 to (2.0+/xe2x88x920.56) inches, and spacing between precordial electrodes V2-V4 to (3.5+/xe2x88x921.0) inches, but also teaches that relative spacing and positioning between V1, V2, V3 and V4 should remain constant in a family of electro-dermal connector devices, where the difference from member to member in said family is found in the spacing between V4-V5 and V5-V6, with demonstrative distances being 1.75, 2.5 and 3.5 inches. It is noted that it is not readily apparent why the Kelly et al. Patent selected the dimensions recited therein, as they do not seem to have any definite scientific basis and no data to show why, for instance positioning precordial leads V1 and V2 with respect to one another outside the range of (2.0+/xe2x88x920.56) inches would result in unacceptable ECG monitoring. It is known by the present inventor, for instance, that, in adults, placing V2 three (3.0) inches from V1, (which is consistant with original published relative anatomic V1 and V2 positioning and still meets present standards), provides excellent ECG monitoring results, as does placing V2 less than one-and-forty-four hundreths (1.44) inches apart in pediatric subject. Another Patent to Kelly et al. is U.S. Pat. No. 6,006,125. This Patent teaches a xe2x80x9cuniversalxe2x80x9d ECG multiple sensor dermal chest mask with indicia thereon for aiding in application to a subject constituting means to align with a mid-sternum and the forth intercostal space, said mask having nine sensors thereon, which nine sensors are selected for application in specific cases to provide three sets of six sensors each, the essential condition being that there are present two sensors which can be selected at each of the V5 and V6 locations, with a third sensor being located thereinbetween which can be used as either a V5 or V6 sensor. The strict dimensions provided, (to the hundredths decimal place or more), it is believed, allow well defined criteria for designing therearound to avoid the Claims which recite restrictive dimensions, and regarding Claims wherein dimensions are not recited, avoidance is believed accomplished by varying the relative positions of V1, V2, V3 and V4 in a family of electro-dermal connector devices, in addition to varying distances between V4-V5 and V5-V6. In fact, scaling all electrode placements in members of a family of electrodes is thought to be preferable by the present inventor. As regards the presence of only two electrodes at V5 and at V6 locations, and the sharing of a third electrode by V5 and V6, it is unclear as to how lateral curents between said V5 and V6 electrodes are to be prevented especially where the electrode which can be a V5 or a V6 is utilized, and it is also unclear as to whether U.S. Pat. No. 5,184,620 to Cudahy et al. was considered in the examination of the 125 Patent Claiming said xe2x80x9cuniversalxe2x80x9d electrode.
Continuing, it is also established that electrode configuration can be important in determining the accuracy of monitored signals. For instance, the use of a Bulls-eye shaped electrode, which comprises a central electrode surrounded by one or more annular ring electrodes, can provide signals which focus upon a specific region of a subject""s heart, which focus is not available when a simple electrode geometry is utilized. As well, Bulls-eye shaped electrodes allow determination of derivatives of detected signals in use.
An article by He et al. titled xe2x80x9cBody Surface Laplacian Mapping of Cardiac Electrical Activityxe2x80x9d published in The American J. of Cardiology, Vol. 70, Dec. 15, 1992 describes the use of Bulls-eye shaped electrodes to map derivatives of cardiogenic signals.
Patents which describe unusual geometrical electrode configurations are, for instance, a Patent to Clare et al., U.S. Pat. No. 5,295,482 which discloses a large surface area electrode in which a central portion is surrounded by two surrounding ring portions., said central and two surrounding ring portions being separated from one another by annular regions. This Patent states that during use in theraputic applications, current density is found to be greater at the outer edge of an electrode than it is at a more central location. The purpose of the described system is disclosed as being to effect a more uniform distribution of current density over the effective large surface area of the disclosed electrode during use, by providing multiple xe2x80x9couter-edgexe2x80x9d providing portions. Other references which describe the xe2x80x9cedge-effectxe2x80x9d are a Patent to Dahl et al., U.S. Pat. No. 5,063,932 and a Canadian Patent No. 1,219,642. In addition, two articles also treat the subject, said articles being: xe2x80x9cOptimal Electrode Designs for Electrosurgery, Defibrillation, and External Cardiac Pacingxe2x80x9d, by Kim et al., which appeared in Transactions On Biomedical Engineering, Vol. BME-33, No. 9, September 1986; and xe2x80x9cAnalysis and Control of the Dispersive Current Distribution under Circular Dispersive Electrodesxe2x80x9d, by Wiley and Webster, which appeared in the IEEE Transactions On Biomedical Engineering, Vol. BME-29, No. 5, in May 1982.
Even in view of the above cited literature, need remains for a convenient to utilize bioelectric interface, which bioelectric interface comprises equivalent Einthoven triangle limb electrodes mounted on a common subject chest applied support sheet, which preferably comprises an electrically anisotropic conducting hydropolymer self adhesive material, which provides electrodes of a composition and geometry appropriate for optimizing electrical contact to a subject, which allows clinically accurately monitored signals to be obtained therefrom during use, and which facilitates a multiplicity of non-monitoring uses such as external cardiac pacing, cardiac defibrillation, electro surgery, electro-ablation processes, and impedance cardiography.
As described in Co-pending application Ser. No. 08/374,873 filed Aug. 16, 1999, the present invention concerns the practice of electrocardiology wherein a number of signals, which are diagnostic of myocardial function, are acquired via sensors placed upon a subject""s body. The present invention differs from previous teachings in that a BIO-ELECTIC INTERFACE ADAPTER WITH TWELVE-LEAD ECG CAPABILITY AND PROVISION FOR DEFIBRILLATION AND/OR PACING is described. In particular, the system of the present invention Bio-electric interface, as regards twelve-lead monitoring capability, remains as previously described in the 873 Application, and disclosure from that Application is incorporated by reference herein, and largly repeated hereafter for emphasis. What is new, novel and non-obvious in this Application, however, is the design of the Bio-electric interface to include not only twelve-lead monitoring capability, but also to includes, amongst other things, provision of standard defibrillation electrodes. This takes at least two forms:
First, the outer edge of the 873 Bio-electric interface can be of an undulated shape, as previously taught in the 873 Application, but undulated appropriately to allow convenient placement of two separate element large-area defibrillation and/or pacing electrodes on a subject simultaneous therewith, (eg. near locations where prior embodiments had placed right-arm and left-leg electrodes and because of their similar size, near conventional locations thereof), and
Second, large-area defibrillation electrodes can be integrally combined as a Bio-electric interface, and in most cases serve as right-arm and/or left-leg electrodes when not being utilized as defibrilltion electrodes, or said large-area defibrillation electrodes can have smaller monitoring limb lead forming electrodes integrally attached thereto or otherwise included therewith. Of course, the presence of perforations, or other functionally equivalent means, to allow easy detachment and deployment of the large-area defibrillation electrodes can be a feature, as can presence of perforations or other functionally equivalent means to allow detachment and deployment of said right-arm and left-leg electrodes from the new Bio-electric interface configuration, for other diagnostic or theraputic purposes.
A present invention bioelectric interface preferably comprises sufficient precordial electrodes to monitor standard twelve lead ECG""s along with said defibrillation electrodes as an integral part thereof. The defibrillation electrodes can be affixed via perforations or functional equivalent, so as to allow easy detachment thereof. The defibrillation electrodes can have affixed thereto electrodes appropriate for use in forming right-arm and left-leg limb leads. The present invention Bioelectric interface can comprise limb lead forming electrodes (RA) (LA) and (LL), and the present invention Bioelectric interface can further comprise a harness thereon to which is affixed, in use, a bundle of wires or tracks for connecting the interface to compatable diagnostic and theraputic systems.
The present invention can be recited as a bioelectric interface comprising at least two defibrillation electrodes as an integral part thereof, said bioelectric interface further comprising sufficient precordial electrodes to monitor standard twelve lead ECG""s. The bioelectric interface can provide the defibrillation electrodes affixed to the bioelectric interface via perforations or functional equivalent, so as to allow easy detachment thereof, and the defibrillation electrodes can have affixed thereto electrodes appropriate for use in forming right-arm and left-leg limb leads. The present invention bioelectric interface preferably further comprises ECG limb electrodes (RA) (LA) and (LL) configured in an RA, LA, LL electrocardiogram system electrode pattern; which RA, LA and LL electrodes, when functionally combined with summing impedances from each thereof, which summing impedances are xe2x80x9cYxe2x80x9d interconnected to provide a Wilson central terminal, form an Einthoven frontal lead triangle with a I, II, III lead pattern when mounted to a subject""s chest, said Einthoven frontal lead triangle with a I, II, III lead pattern being positioned on said subject""s chest so as to provide a voltage which presents at said Wilson central terminal which is within a selected range of deviation from a voltage which would appear at a Wilson central terminal formed from summing impedances from conventional limb mounted electrodes which are xe2x80x9cYxe2x80x9d interconnected, (both voltages being with resepct to some reference). In addition, the present invention bioelectric interface can further comprise at least one selection from the group consisting of:
said bioelectic interface comprises a harness thereon to which is affixed, in use, a bundle of wires or tracks for connecting to diagnsotic and/or theraputic systems;
said at least two defibrillation electrodes are connected to a source of defibrillation electrical energy;
said precordial electrodes are connected to a system for monitoring twelve lead ECG""s.
six precordial and three limb lead electrodes are located as:
electrode region RA generally in the region of the first or second intercostal space to the right of the sternum;
electrode region LA generally in the region of the left third or fourth intercostal space at the mid-axillary line;
electrode region LL generally in the region of the inferior costal margin in the left mid-clavicular line;
electrode region V1 in the region of the fourth intercostal space at the right sternal border;
electrode region V2 in the region of the fourth intercostal space at the left sternal border;
electrode region V4 in the region of the fifth intercostal space at the left mid-clavicular line;
electrode region V3 in the region of the midpoint between electrode regions V2 and V4;
electrode region V5 in the region of the fifth intercostal space in the left anterior axillary line; and
electrode region V6 in the region of the fifth intercostal space in the mid-axillary line.
Another recitation of a present invention bioelectric interface provides that it comprise a carrier matrix in functional combination with at least two spatially separated defibrillation electrodes, and V1, V2, V3, V4, V5, and V6 precordial electrodes and RA, LA and LL limb lead forming electrodes, said electrodes being affixed to said carrier matrix in a manner such that their relative positions with respect to one another are essentially fixed, said RA, LA, LL limb lead electrodes being positioned such that when functionally combined with summing impedances from each thereof, which summing impedances are xe2x80x9cYxe2x80x9d interconnected to provide a Wilson central terminal, form an Einthoven frontal lead triangle with a I, II, III lead pattern when mounted to a subject""s chest, said Einthoven frontal lead triangle with a I, II, III lead pattern being positioned on said subject""s chest so as to provide a voltage which presents at said Wilson central terminal which is within some selected range of deviation from a voltage which would appear at a Wilson central terminal formed from summing impedances from conventional limb mounted electrodes which are xe2x80x9cYxe2x80x9d interconnected. Said bioelectric interface preferably further comprises an adhesive comprised of electrically conductive polymer which is hydrophillic, and thereby particularly well suited for application to human skin. Further, said electrodes are each of a construction such that contact with the adhesive sheet is essentially continuous over the dimension of each said electrode, and at least one of said electrodes can be of a multiple-piece construction such that each of said multiple pieces contacts the adhesive independently and essentially continuously over the dimension of each said multiple pieces, (eg. multipiece construction configures a Bulls-eye pattern). It is further noted that the adhesive sheet can be affixed so as to sandwich said electrodes between said carrier matrix and said adhesive sheet, the purpose being to improve subject adherence. Also, said bioelectric interface can further comprise means for electrically connecting said electrodes to external devices. It is further noted that the adhesive sheet preferably simultaneously presents with essentially anisotropic specific, (ie. bulk), impedance properties and essentially isotropic pliability and adhesion mechanical properties, electrode(s) in each of said spatially separated regions of electrode(s) being affixed to said adhesive sheet in a manner such the relative positions of electrodes present with respect to one another are essentially fixed, and such that the specific impedance from each electrode in said regions of spatially separated electrode(s) directly through the thickness of said adhesive sheet, is less than that between any two electrodes in different spatially separated regions of electrodes) through said adhesive sheet, said electrical anisotropic specific impedance properties of said adhesive sheet being the result of at least one selection from the group consisting of:
scrim therein, which scrim is a web of disimilar materials, (or a material with regionally altered characteristics), with relatively electrically conductive adhesive material present in open areas of said web so as to form channel regions of electrically conductive adhesive material bordered by said scrim material, such that adhesive material in one channel region does not contact that in other regions; and
slits therein, which slits are positioned between electrodes.
A method of defibrillating a subject comprising the steps of:
a. providing a bioelectric interface as described; and
b. affixing said bioelectric interface to a subject and causing the defibrillation electrodes therein to be electrically attached to a defibrillation system and applying a defibrilating shock therewith through said defibrillation electrodes.
Said method can further comprise performing a procedure selected from the group consisting of;
a. cardio-pulmonary resuscitation
b. ECG monitoring;
c. cardiac pacing;
d. electro surgery;
e. electro-ablation;
f. impedance cardiography;
g. transdermal drug or nutrient transfer; and
h. electromechanical energy transfer or detection
on said subject without removing said bioelectric interface.
A present invention bioelectric interface can be characterized by at least one selection from the group consisting of:
a. an adhesive sheet is affixed to said support sheet on a subject contacting side thereof and simultaneously presents with essentially anisotropic electrical impedance properties and essentially isotropic mechanical pliability and adhesion properties, said electrodes being affixed to said adhesive sheet such that the impedance from each said electrode directly through the thickness of said adhesive sheet, is less than that between any two of said electrodes through said adhesive sheet;
b. perforations are present in said support sheet which allow easy detachment and deployment of at least one of said Einthoven frontal lead triangle RA, LA and LL electrodes, so that said at least one of said Einthoven triangle RA, LA, and LL electrodes is/are, in use, positionable at locations selected from the group consisting of:
in contact with a subject""s chest; and
in conventional Einthoven triangle forming subject limb positions;
c. perforations are present in said support sheet which allow easy detachment and deployment of at least one of said defibrillation electrodes;
d. an undulated outer edge on said bioelectric interface support sheet; and
e. at least one hole through said bioelectric interface support sheet which allows access to the skin of a subject to which it is affixed in use, (note, support sheet material retained from the hole can serve to form an attached xe2x80x9cflapxe2x80x9d, to which, for instance, a wire harness can be secured in use).
f. at least one said electrocardiogram system electrode which comprises spring-loaded means on a non-subject contacting side thereof, which spring-loaded means develops compression derived force when caused to be compressed, the purpose thereof being to facilitate electrical contact to an electrically conductive element caused to be placed in contact therewith in use, by development of said compression derived force.
Another recitation of a present invention embodiment provides that it be a combination of two defibrillation electrodes and a bioelectric interface which comprises a support sheet in which are affixed sufficient precordial and limb lead forming electrodes to enable standard twelve lead ECG monitoring, said bioelectric interface having an undulated outer edge. The support sheet can have at least one hole, (and optionally a xe2x80x9cflapxe2x80x9d), therein for use in aligning with subject anatomy, (over for instance the Sternum). Further, the undulations in the support sheet and the shape of the defibrillation electrodes are such as to closely mate. Where a flap is present it can serve as a force absorbing support for attaching a cable bundle to the bioelectric interface.
(Note, as discussed in the Detailed Disclosure Section of this Specification, FIGS. 8b and 10a-10e provide insight to exemplary present invention Bio-electric interface embodiements which include two defibrillation electrodes, as well as sufficient precordial and limb lead forming electrodes to enable standard twelve-lead monitoring capability).
Continuing, for general insight and as disclosed in prior Applications from which this Application continues, it is to be appreciated that the practice of electrocardiography involves subject contacting electrodes spatially oriented in lead configurations such as Einthoven triangle, Frank, McFee, Schmidt, twelve-lead configurations etc., and in array patterns for use in mapping, etc., and the present invention bioelectric interface continues as a system which provides Right-Arm (RA), Left-Arm (LA) and Left-Leg (LL) electrodes which form, when applied to a subject""s chest in use, an Einthoven frontal lead triangle with an equivalent I, II, III lead pattern, said pattern being determined as acceptable by presentation of a voltage with respect to a reference at a formed Wilson central terminal, which voltage with respect to a reference is within a selected range of deviation from a voltage with respect to a reference presented at a conventionally formed Wilson central terminal using conventional subject limb positioning of RA, LA and LL electrodes. The present invention bioelectric interface further provides all necessary electrodes, appropriately configured for mounting to a subject""s chest, for use with electrocardiograph systems, and in the most recent embodiment provides provision for simultaneous presence of defibrillation electrodes, either as separate elements, or as an integral part of the Bio-electric interface.
As demonstrated in the Background Section of this Disclosure, multiple electrode systems are not unknown. However, said known systems do not provide all electrodes for use with a twelve-lead electrocardiogram (ECG) system conveniently positioned on a bioelectric interface which can be easily, accurately and repeatably applied to a subject""s chest in a desired anatomical orientation. A twelve-lead (ECG) system, by conventional practice, requires that electrodes be placed on a subject""s Right (RA) and Left (LA) arms and Left leg (LL), and that six precordial electrodes (V1, V2, V3, V4, V5, and V6), be placed upon the subject""s chest. The locations of the V1-V6 electrodes are:
V1xe2x80x94in the region of the fourth intercostal space at the right sternal border;
V2xe2x80x94in the region of fourth intercostal space at the left sternal border;
V4xe2x80x94in the region of fifth intercostal space at the left mid-clavicular line;
V3xe2x80x94in the region of the midpoint between the V2 and V4 electrodes;
V5xe2x80x94in the region of the fifth intercostal space at the left anterior axillary line;
V6xe2x80x94in the region of the fifth intercostal space in the left mid-axillary line.
No known reference, however, suggests that arm and leg equivalent electrodes should be placed at chest locations relatively near the precordial electrodes. The present invention teaches that said arm and leg equivalent electrodes are to be so placed. The location of said arm and leg equivalent electrodes is best understood by reference to the Drawings which are discussed in the Detailed Description of this Disclosure, however, verbally their positioning can be generally described as, in a non-limiting manner, as:
Right Armxe2x80x94generally in the region of the first or second intercostal space to the right of the sternum;
Left Armxe2x80x94generally in the region of left thrid or fourth intercostal space at the mid-axillary line; and
Left Legxe2x80x94generally in the region of the inferior costal margin in the left mid-clavicular line.
It is emphasized that where limb lead forming electrode placement is the topic, it is the functional achievement of a Wilson Central Terminal voltage to which precordial lead electrode signals can be compared which is important, rather than precise subject referenced anatomical positioning of electrodes.
In addition, the present invention teaches the optional use of multiple electrode element electrodes, (eg. xe2x80x9cBulls-eyexe2x80x9d shaped electrodes), for instance, in a multiple electrode element electrode system. Use of single electrode element xe2x80x9cButtonxe2x80x9d electrodes is conventional, and in use each such Button electrode serves to measure an electrical signal between it and a common or reference electrode, (typically termed uni-polar electrodes), or a similar button electrode (typically termed Bi-polar electrodes). When multiple electrode element (eg. Bulls-eye), electrodes are utilized, however, signals are generated between two components of a single electrode. Continuing, a Bulls-eye shaped electrode is typically configured like a xe2x80x9ctargetxe2x80x9d. That is, typically a Button electrode will be centrally located within an outer annular shaped electrode. The benefits provided by such multi-electrode element electrodes are the ability to achieve greater resolution of signals generated in a specific area of a subject""s heart, and it is noted, that the signals measured are representative of the derivatives of electrical signal activity produced by a subject""s heart. That is, the signal provided between a Button and First Annulus is proportional to a derivative of a signal generated by a subject""s heart. Additional annular ring electrodes can also be present and signals measured thereby are proportional to higher order derivatives. Use of Bulls-eyexe2x80x9d electrode geometry then allows investigation of High Frequency aspects of electrical activity generated by a subject""s heart. It is noted that a limitation is associated with the use of Bulls-eye electrodes in that the smaller they are dimensioned, although enabling increased resolution and investigation of electrical signals generated in smaller regions in a heart, the smaller the magnitude of signal they provide. In a multiple electrode setting then, where relative motion between electrodes can create confounding electrical noise, it then becomes increasingly important to prevent relative motion between electrodes and components of Bulls-eye electrodes, when Bulls-eye electrodes are present. (Note, it is emphasized that it is possible to achieve a result similar to that provided by xe2x80x9cBulls-eyexe2x80x9d electrodes with other multiple element electrodes, and for the purposes of this Disclosure any functionally similar electrode is to be considered as included by the terminology xe2x80x9cBulls-eyexe2x80x9d whether a closed annulus is present or not).
It is also to be understood that a present invention electrode can consist of a plurality of electrode elements, (eg. a plurality of button shaped electrode elements), configured in a region of the bioelectric interface which, in use, aligns with an anatomical location appropriate for use in a standard twelve-lead (ECG) system.
With the forgoing in mind, it is then to be appreciated that the system of the present invention is a bioelectric interface comprised of a plurality of electrodes which are affixed to a support sheet in a desired spatially separated pattern, such that in use said electrodes are essentially fixed in location with respect to one another. It is noted that fixing said relative position between electrodes, and between electrode elements, serves to reduce electrical noise which can be generated when, in use, electrodes move with respect to one another. Again, it is to be understood that the electrodes can be of single electrode element, or multiple electrode element Button or Bulls-eye, (or other), geometry.
Continuing, a typical present invention bioelectric interface has an adhesive material present over at least a portion of a surface thereof which contacts a subject in use. The adhesive material of the present invention can have the properties of simultaneously demonstrating essentially electrically anisotropicity, but isotropic mechanical (eg. pliability and adhesion), properties. That is, the specific, (or bulk), impedance across the adhesive material can be significantly different from that laterally directed, but the mechanical properties such as adhesion and pliability are typically essentially consistent. (Note, the term xe2x80x9cspecific impedancexe2x80x9d is used to refer to the regional bulk property of the adhesive material, rather than properties resulting from dimensions of sheets fabricated therefrom). In the preferred embodiment, the adhesive material is a hydropolymer sheet which demonstrates a tackiness on a subject skin contact side thereo. Hydropolymers are particularly applicable in realization of the present invention as they are electrically conductive, relatively nonirritating to a subject""s skin, and they demonstrate excellent adhesive qualities. Commercially available hydropolymer sheets with isotropic electrical properties, are available under the Tradename xe2x80x9cPromeonxe2x80x9d from the Ludlow Group of Springfield Mass., under the product designation of RG-60 Series Hydrogels. Lec-Tec of Minneapolis, Minn. also markets hydrogels. The present invention provides that such adhesive hydropolymer sheet material can be utilized, if xe2x80x9cslitsxe2x80x9d are entered thereto at appropriate locations to effect electrical anisotropicity between electrodes present at various laterally offset locations. It is noted that hydropolymer sheets do not typically demonstrate a rigidity sufficient to maintain a spatially stable relationship between electrodes affixed thereto, but particularly when slits are formed therein, hence, the present invention requires that a support sheet carrier matrix be present to which electrodes and said adhesive sheet attach. That is, the system of the present invention will then comprise a support sheet carrier matrix to which are attached, at desired spatially offset locations, electrodes, over which configuration said hydropolymer is placed so that said electrodes are sandwiched between said carrier matrix and hydropolymer. At locations between the various electrodes said xe2x80x9cslitsxe2x80x9d are then caused to be present by, typically, a mechanical process. It is noted that in practice said slits need not be of a degree to provide complete discontinuity between various regions of the resulting hydropolymer system to provide a sufficiently anisotropic specific impedance system. The Background Section also identifies various electrically anisotropic adhesive materials. The present invention, in addition, teaches that an essentially electrically anisotropic adhesive material sheet can be provided by a xe2x80x9cScrimxe2x80x9d material comprising a number of channels therethrough, which channels are caused to be filled with an electrically conductive adhesive material, (preferably a hydropolymer), such that xe2x80x9cisland channelsxe2x80x9d of conductive material exist across the resultant sheet, but such that electrically nonconductive scrim exists between laterally oriented islands of conductive material. The xe2x80x9cScrimxe2x80x9d can be electrically conductive carbon fibers, and/or electrically non-conducting plastic filaments, or materials which have been regionally altered to vary conductivity from one region to another, as required to provide a desired electrical anisotropicity.
It is also noted that as the relative spatial separation of various electrodes is essentially fixed by the present invention, and as their position on a subject""s body is typically secured by an adhesive sheet, it is possible to conduct activities such as cardio-pulmonary-resuscitation (CPR) on a subject to which the present invention bioelectric interface is applied, without removal thereof. Such is essentially impossible where individual leads are utilized in an (ECG) system. As well, the present invention teaches that the means for making electrical contact to the electrodes should be available on the outer, non-subject contact, surface of the bioelectrical interface. For instance, snaps might be provided so that leads from any (ECG) system can easily attach thereto, or so that conductive tracks can be employed to bring signals to a manifold or connector means for convenient electrical access.
It is also emphasized that the electrodes in the bioelectric interface, being electrically conductive, enable, in an emergency, the application of defibrillation via xe2x80x9cmetal-paddle-typexe2x80x9d electrodes to said interface means for making intimate electrical contact to said electrodes without removing the present invention bioelectrical interface from the subject. And, because the present invention is firmly affixed to a subject, the defibrillation shock will be safely transmitted to the subject with little, or no attenuation. It is also emphasized that in use, first and second conventional paddles of a defibrillation system can be caused to contact first and second spatially separated groups of electrodes in the bioelectric interface, press contacted electrodes into good electrical contact with the subject, and deliver electrical defibrillating pulse energy therethrough. Further, the presence of multiple electrodes, (and even multiple electrode elements within an electrode), within a defibrillation paddle-sized cluster of electrodes, through which defibrillation electrical energy can be delivered to a subject, serve to reduce adverse edge effects associated with applying defibrillation electrical energy through single element paddle, (or pad), electrodes. Special electrodes can be specifically designed which serve to reduce edge effects, and use thereof in the present invention Bio-electric interface is within the scope of the present invention.
One can also utilize one or more electrodes in the present invention bioelectric interface for heart pacing, electrosurgery, electro ablation, impedance cardiography, transdermal drug or nutrient transfer and electromechanical energy transfer.
The present invention bioelectric interface can be better described, in its most basic form, as comprising a support sheet in functional combination with at least three (3) spatially separated electrocardiogram system electrodes, with each of said at least three (3) spatially separated electrocardiogram system electrodes being a single electrical electrode element or a group of electrically independent electrode elements. Each of said spatially separated electrocardiogram system electrodes is affixed to said support sheet in a manner such that the relative positions of said electrocardiogram system electrodes with respect to one another are essentially fixed therewithin. Three (3) of said at least three (3) electrocardiogram system electrodes being configured in an RA, LA, LL electrocardiogram system electrode pattern. The positioning of said three (3) electrocardiogram system electrodes as applied to a subject""s chest during use can, in a non-limiting manner, be exemplified as follows:
electrode RA being generally in the region of the first or second intercostal space to the right of the sternum;
electrode LA being generally in the region of the left third of fourth intercostal space in the mid-axillary line;
electrode LL being generally in the region of the inferior costal margin in the left mid-clavicular line;
Further, said electrodes RA, LA and LL form, when applied to a subject""s body in use, an Einthoven frontal lead triangle with an equivalent I, II, III lead pattern which is determined as acceptable by presentation of a voltage with respect to a reference at a formed Wilson central terminal, which voltage with respect to a reference is within a selected range of deviation from a voltage with respect to a reference presented at a conventionally formed Wilson central terminal using conventional subject limb positioning of RA, LA and LL electrodes. Said user selected range of voltage deviation can be selected to be less than one (1.0) millivolt, one (1.0) millivolt, or greater than one (1.0) millivolt.
The present invention bioelectric interface can further comprise an equivalent electrocardiogram system RL electrode, and said RA, LA, LL and RL electrodes can be present in the support sheet such that perforations allow easy detachment of said equivalent electrocardiogram RA, LA, LL and RL electrodes, in use, thereby allowing them to be automatically positioned at a location in contact with a subject""s chest, or by manual manipulation, in conventional subject limb positions.
The present invention bioelectric interface support sheet is typically at least partially covered with an adhesive material on a subject contacting side thereof, and said adhesive material can present with electrical conductive properties which can be isotropic, or regionally anisotropic such that the specific impedance through said adhesive material in certian areas is less than that in a laterally oriented direction. Said regional anisotropic electrical conductive properties of said adhesive material can be effected, as described infra herein, by the presence of an electrically conductive and/or nonconductive scrim patterned therein so as to form channel regions of electrically conductive adhesive material through said adhesive material bordered by said scrim material, such that adhesive material in one channel region does not contact that in other regions. An alternative approach to effecting said regional anisotropic electrical conductive properties of the adhesive material involves the placing of slits therein. Said adhesive material can be a hydropolymer and it can be caused to cover essentially the entire subject contacting surface of said support sheet.
As mentioned, at least one of said spatially separated electrocardiogram system electrodes can be of a construction consisting of a group of electrically independent electrode elements, and said elements can be configured in, for instance, Bulls-eye and multiple button shaped electrode elements patterns.
A method of providing an Einthoven triangle equivalent RA, LA, LL pattern of electrodes on the chest of a subject, utilizing the present invention bioelectric interface, can comprise the steps of:
a. Providing a present invention bioelectric interface comprising a support sheet in functional combination with at least three (3) spatially separated electrocardiogram system electrodes as already described, wherein at least one (1) of said at least three (3) spatially separated electrocardiogram system electrodes is of a construction consisting of a group of electrically independent electrode elements. As described above, each of said spatially separated electrocardiogram system electrodes is affixed to said support sheet in a manner such the relative positions of said electrocardiogram system electrodes with respect to one another are essentially fixed therewithin. Three (3) of said at least three (3) electrocardiogram system electrodes are configured in an RA, LA, LL electrocardiogram system electrode pattern, such that said three (3) electrocardiogram system electrodes can be applied on a subject""s chest during use as follows:
electrode RA being generally in the region of the first or second intercostal space to the right of the sternum;
electrode LA being generally in the region of the left third or fourth intercostal space in the mid-axillary line;
electrode LL being generally in the region of the inferior costal margin in the left mid-clavicular line;
Also as described above, said electrodes RA, LA and LL form, when applied to a subject""s body in use, an Einthoven frontal lead triangle with an equivalent I, II, III lead pattern which is determined as acceptable by presentation of a voltage with respect to a reference at a formed Wilson central terminal, which voltage with respect to a reference is within a selected range of deviation from a voltage with respect to a reference presented at a conventionally formed Wilson central terminal using conventional subject limb positioning of RA, LA and LL electrodes. Said user selected range of voltage deviation can be selected to be less than one (1.0) millivolt, one (1.0) millivolt, or greater than one (1.0) millivolt;
b. Applying said bioelectric interface to a subject;
c. Selecting at least one electrically independent element in each of said at least one electrocardiogram system RA, LA and LL electrode(s) consisting of a group of electrically independent electrode elements;
d. Connecting said selected electrocardiogram system electrically independent element(s) in each of said RA, LA and LL electrode(s) to appropriate inputs of an electrocardiogram system.
Continuing, a preferred embodiment of the present invention bioelectric interface comprises a support sheet in functional combination with at least nine (9) spatially separated electrocardiogram system electrodes. Each of said at least nine (9) spatially separated electrocardiogram system electrodes being a single electrical electrode element or a group of electrically independent electrode elements. Each of said spatially separated electrocardiogram system electrodes is affixed to said support sheet in a manner such the relative positions of said electrocardiogram system electrodes with respect to one another are essentially fixed therewithin, with nine (9) of said at least nine (9) electrocardiogram system electrodes being configured in an RA, LA, LL, V1, V2, V3, V4, V5, V6 electrocardiogram system electrode pattern. In use, said nine (9) electrocardiogram system electrodes can be applied to a subject""s chest during use as follows:
electrode RA being generally in the region of the first or second intercostal space to the right of the sternum;
electrode LA being generally in the region of the left third or fourth intercostal space in the mid-axillary line;
electrode LL being generally in the region of the inferior costal margin in the left mid-clavicular line;
Said electrodes RA, LA and LL form, as described infra herein, when applied to a subject""s body in use, an Einthoven frontal lead triangle with an equivalent I, II, III lead pattern which is determined as acceptable by presentation of a voltage with respect to a reference at a formed Wilson central terminal, which voltage with respect to a reference is within a selected range of deviation from a voltage with respect to a reference presented at a conventionally formed Wilson central terminal using conventional subject limb positioning of RA, LA and LL electrodes. Said user selected range of voltage deviation can be selected to be less than one (1.0) millivolt, one (1.0) millivolt, or greater than one (1.0) millivolt.
The V1, V2, V3, V4, V5, V6 electrocardiogram system precordial electrode pattern is formed as:
electrode V1 in the region of the fourth intercostal space at the right sternal border;
electrode V2 in the region of the fourth intercostal space at the left sternal border;
electrode V4 in the region of the fifth intercostal space at the left mid-clavicular line;
electrode V3 in the region of the midpoint between electrode groups V2 and V4;
electrode V5 in the region of the fifth intercostal space in the left anterior axillary line; and
electrode V6 in the region of the fifth intercostal space in the left mid-axillary line.
The described preferred embodiment of the present invention can also further comprise an equivalent electrocardiogram system RL electrode, and perforations can be present in said support sheet to allow easy detachment and deployment of said equivalent electrocardiogram RA, LA, LL and RL electrodes, in use, so that they can be positioned in contact with a subject""s chest, or in conventional subject limb position.
As described above, the presently described present invention bioelectric interface support sheet is also typically at least partially covered with an adhesive material on a subject contacting side thereof, which adhesive material presents with electrical conductive properties which can be isotropic or regionally anisotropic such that the specific impedance through said adhesive material is less than that in a laterally oriented direction. As also already discussed, a preferred adhesive material is hydropolymer which covers essentially the entire subject contacting surface of said support sheet.
Also as discussed above, each of the electrodes can be of a construction consisting of a group of electrically independent electrode elements, such as a Bulls-eye pattern, and multiple button shaped electrode elements.
A method of defibrilating a subject can comprise the steps of:
a. Providing a bioelectric interface comprising a support sheet in functional combination with at least two (2) spatially separated defibrillation electrodes, as just described;
b. Affixing said bioelectric interface to a subject as described above, and causing electrodes therein to be electrically attached to a defibrillation system and delivering a defibrillation shock.
Said method of acquiring electrocardiographic data said method of acquiring electrocardiographic data can further include the step of removing and deploying said electrodes RA, LA and LL configured in an Einthoven frontal triangle equivalent LA, RA, LL pattern, utilizing perforations in said support sheet, and affixing said RA, LA and LL electrodes to conventional subject limb locations.
A method of utilizing any present invention bioelectric interface during formation of an Einthoven triangle equivalent or during acquisition of electrocardiographic data, can further comprise the simultaneous step of performing a procedure selected from the group consisting of;
a. cardio-pulmonary resuscitation
b. ECG monitoring;
c. cardiac pacing;
d. electro surgery;
e. electro-ablation;
f. impedance cardiography;
g. transdermal drug or nutrient transfer; and
h. electromechanical energy transfer or detection;
on said subject without removing said bioelectric interface.
Where defibrillation is performed, two conventional defibrillation paddles are positioned so that a first conventional defibrillation paddle contacts at least two of said electrocardiogram system electrodes, and a second said conventional defibrillation paddles contacts at least two of said electrocardiogram system electrodes, said two at least electrodes contacted by said first conventional defibrillation paddle being different than, and spatially separated from, said at least two electrodes contacted by said second conventional defibrillation paddle. In use, electrodes contacted by defibrillation paddles are caused to be pressed firmly into good contact with a subject. The result of the presence of multiple electrodes being that defibrillation pulse current distribution electrode edge effects are reduced.
It is further noted that the voltage present at a formed Wilson central terminal can be a root-mean-square value of a selected portion of a subject electrocardiogram system monitored electrocardiogram cycle, such as the QRS complex.
Finally, it is noted that a conventional Wilson central terminal is a central xe2x80x9cYxe2x80x9d interconnection point of fixed value, (eg. 10,000 ohm), resistors attached to RA, LA and LL electrodes. The present invention provides that at least one of said resistors can be variable and can, in use, be adjusted and thereby set a Wilson central terminal voltage produced by use of a present invention Bioelectric Interface, to a desired value. The application of variable resistors in forming a Wilson central terminal in combination with a present invention Bioelectric Interface, to effect production of a Wilson central terminal voltage which is within a desired deviation value with respect to a similar voltage which would be obtained utilizing conventional limb positioned electrodes, is not, to the inventor""s knowledge, obviated in any known rerference or combination of references.
The present invention will be better understood by reference to the Detailed Description Section in conjunction with the accompanying Drawings.
It is a primary purpose of the present invention to teach a bio-electric interface for application to a subject""s chest during use, should be comprised of electrodes for monitoring ECG data, as well as providing for simultaneous presence of electrodes for applying defibrillation shocks, either as separate elements or integrated into said a bio-electric interface.
It is another primary purpose of the present invention to teach that electrodes configured in an RA, LA, LL electrocardiogram system electrode pattern in a bio-electric interface should be applied to a subject""s chest during use, the positioning of said electrocardiogram system electrodes being exemplified as:
electrode RA being generally in the region of the first or second intercostal space to the right of the sternum;
electrode LA being generally in the region of the left third or fourth intercostal space at the mid-axillary line;
electrode LL being generally in the region of the inferior costal margin in the left mid-clavicular line;
said electrodes RA, LA and LL forming an Einthoven frontal lead triangle with an equivalent I, II, III lead pattern which is determined as acceptable by presentation of a voltage with respect to a reference at a formed Wilson central terminal, which voltage with respect to a reference is within a selected range of deviation from a voltage with respect to a reference presented at a conventionally formed Wilson central terminal using conventional subject limb positioning of RA, LA and LL electrodes. (Said user selected range of voltage deviation can be selected to be less than one (1.0) millivolt, one (1.0) millivolt, or greater than one (1.0) millivolt).
It is another primary purpose of the present invention to teach that electrodes configured in an RA, LA, LL electrocardiogram system electrode pattern in a bio-electric interface should be applied to a subject""s chest during use, the positioning of said electrocardiogram system electrodes being such that said electrodes RA, LA and LL form an Einthoven frontal lead triangle with an equivalent I, II, III lead pattern which is determined as acceptable by presentation of a voltage with respect to a reference at a formed Wilson central terminal, which voltage with respect to a reference is within a selected range of deviation from a voltage with respect to a reference presented at a conventionally formed Wilson central terminal using conventional subject limb positioning of RA, LA and LL electrodes. (Said user selected range of voltage deviation can be selected to be less than one (1.0) millivolt, one (1.0) millivolt, or greater than one (1.0) millivolt).
It is another purpose of the present invention to teach that six precordial electrodes (V1, V2, V3, V4, V5, and V6) in said bioelectric interface, should also be placed upon the subject""s chest in combination with said RA, LA and LL electrodes. The locations of the V1-V6 electrodes being exemplified as:
V1xe2x80x94in the region of the fourth intercostal space at the right sternal border;
V2xe2x80x94in the region of fourth intercostal space at the left sternal border;
V4xe2x80x94in the region of fifth intercostal space at the left mid-clavicular line;
V3xe2x80x94in the region of the midpoint between the V2 and V4 electrodes;
V5xe2x80x94in the region of the fifth intercostal space at the left anterior axillary line;
V6xe2x80x94in the region of the fifth intercostal space in the left mid-axillary line.
It is yet another purpose of the present invention to teach the use of multiple electrode element electrodes, (eg. xe2x80x9cBulls-eyexe2x80x9d shaped electrodes), as well as single electrode element xe2x80x9cButtonxe2x80x9d electrodes in a bioelectric interface.
It is still yet another purpose of the present invention to teach a bioelectric interface which has an adhesive material present over at least a portion of a surface thereof which contacts a subject in use.
It is yet still another purpose of the present invention to teach a bioelectric interface in which the adhesive material is a hydropolymer.
It is another purpose of the present invention to teach a bioelectric interface in which the adhesive material demonstrates anisotropic specific impedance.
It is yet another purpose of the present invention to teach a method of utilizing any present invention bioelectric interface during formation of an Einthoven triangle equivalent or during acquisition of electrocardiographic data, which further comprises the simultaneous step of performing a procedure selected from the group consisting of;
a. cardio-pulmonary resuscitation
b. ECG monitoring;
c. cardiac pacing;
d. electro surgery;
e. electro-ablation;
f. impedance cardiography;
g. transdermal drug or nutrient transfer; and
h. electromechanical energy transfer or detection;
on said subject without removing said bioelectric interface.
It is still yet another purpose of the present invention to teach a bioelectric interface comprised of a plurality of electrodes which are affixed to a support sheet in a desired spatially separated pattern, such that in use said electrodes are essentially fixed in location with respect to one another such that confounding noise signals resulting from relative motion between said electrodes are reduced in use.
It is another purpose of the present invention to teach the use of variable resistor(s) in formation of a Wilson central terminal. The purpose thereof being to allow adjustment of a voltage appearing at a Wilson central terminal formed utilizing present invention Bioelectric Interface RA, LA and LL electrodes, so that it is within a desired range of deviation from a Wilson central terminal voltage obtained utilizing conventionally placed limb electrodes.
Other objectives and/or purposes will become apparent by refrence to the Specification.